Method and apparatus for transforming direct current



Feb. 12 1924.

:G. B. COLEMAN METHOD AND APPARATUS FOR TRANSFQRMING DIRECT CUfiRENT Fil ed Oct. 16.1919

} 2 sums-sum 1 EMF IMF

. u g M a N J R A M m w Feb. 12 1924.

G. B. COLEMAN METHOD AND APPARATUS FOR TRANSFORMING DIRECT CURRENT.

2 Sheets-Shoot 2 Filed Oct. 16 1919 m ywfm w fiwz m 1977084 5 Patented UNITED STATES PATENT OFFICE,

GEORGE B. COLEMAN, OF SAN FBANCI X-RAY COMPANY, OF SAN FRANCISC FOBNIA.

SCO, CALIFORNIA, ASSIGNOB TO COLEMAN 0, CALIFORNIA, A CORFORATION OF'CAIII- METHOD AND APPARATUS FOR TRANSFOBMING DIRECT CUB/RENT.

Application filed October 16, 1919. Serial No. 331,034.

T 0 all whom it may concern:

Be it known that I, G

noncn B. COLEMAN,

a citizen of the United States, and a resident of the ciy State of 'useful Improvements in paratus for Transforming, of which the followin My invention has for its obje duction of a secondary sired voltage mary, and inc an induced uni invented new alifornia, have Methods and from a and county of San Francisco and Ap- Direct Current, g is a specification.

ct the procurrent of any dedirect current priludes the production of either directional or of an alternating "current, depending upon the means and manner of employ fully in the accompany ifications.

In Fig. 1 I have ment, as set forth 1ng figures and specshown diagrammatically a primary direct current circuit and a sec ondary, or induced, alternating cuit, with the diagrammatic transformer win selector in combination therewith.

Fig. 2 is a primary circuit having electromotive force, an current secondary circuit ing or selecting means interposed in transformer circuit.

Fig. 3 shows diagramma circuit, having an impres tromotive shaft of my rectifie mutators current c1r-' dings and a showing of my rectifier or diagrammatic showing of a an impressed direct d an induced direct with my rectify the tically a primary sed direct elecforce, and an induced secondary direct electromotive force.

Fig. 4 indicates diagrammatically on the and brushes transformer coils of Figures 1 and 2.

Fig. 5 shows t mutator for the rect winding of Fig. 2 wi to the commutator segments of rrangement of the comthe rectifier as appli us shown in Fig. 3.

Fig. 6 shows the a mutator segments in cable to the apparat With each Figure curve of impressed the transformer primary sponding circuit.

Throughout the refer to similar A source of d by the generator 1, connected throu h switch 2,

Fig. i.

1, 2, 3, is shown r the two adjacent comfor the primary h arrangement of the comifier on the secondary th its relative position the electromotive force in and the correderived wave of the secondary arts.

and rheostat device 3, an

figures like numerals irect current is indicated, as

a the The division between 7 and 8,

circuit 4, 5; within which is the primary winding of the transformer 6. This primary winding consists of two coils wound in opposite directions, each of which is divided .at. its neutral, or central, point, thus consisting in effect of four coils 7, 8; 9, 1() and between 9 and 10 is provided with a make and break device 11 and 12 respectively.

In Figure 4 I have shown diagrammatcally the arrangement of the commutator segments 11, 12, on the shaft 13 by which it will be seen that in the positions of the commutators shown, the circuit will be complete through the coils 7 and 8, and when the shaft 13. has rotated sufficiently the circuit will be interrupted between 7 and 8, and will have been completed between 9 and 10. The rotation of the shaft 13 will therefore cause a current to alternate between the two primary windings of the transformer 6, such that the excitation of 7, 8, will alternate with the excitation of 9, 10. These windings being wound in opposite directions, there will be produced an alternating primary excitation in, the transformer 6, which will result in an alternating derived electromotive force in the secondary winding 14, and therefore in the secondary circuit 15, 16, which may be employed for any useful purpose.

The frequency of the derived alternating electromotive force will correspond with the frequency of alternations in the primer occasioned by the revolution of the sha t 13, and makin and breaking of the conductivity of the primary windings; and the shaft 13 may be advantageously operated from a motor in circuit with the secondary 14.

In Fig. 2the same form of interrupter (as shown in Fig. 4) is used in the primar windings, and on the shaft 13 thereof I mount the additional commutator 19, as shown in Fig. 5, interposed at the central point of the transformer secondary winding 17, 18, and which is adapted to operate in step with 11 and 12, and by its action to complete the conductivity of 17, 18, during the conduction period of one of the primary windings as 7, 8, and to interrupt said conductivit between 7, 8, during the conductivityo 9, 10.

It will thus be seen thatby the arrangement set forth in Fig. 1 we are deriving an alternating current from the transformer secondary, the primary windings of which transformer are energized from a direct current source, whereas, with the arrangement as shown in Fig. 2 we are deriving unidirection current, as indicated at 24, 25, 26, from the secondary windin of the transformer, the primary windings of which transformer are energized from a direct current source.

In Fig. 3 the transformer 6 is provided with a primary coil 27, 28, divided at its central point, having interposed therein a periodic interrupter 33 adapted to alternately complete and to interrupt the conductivity between 27 28 to accomplish the wave! form as shown at 30, 31, 32. The secondary winding 29 is herein energized during t e periods of conductivity between 27 and 28, and will consequently deliver a series of uni-direction current waves as 30, 31, 32.

The impressed energization from the direct current source 1 is shown by the broken line 24;, wherein the spaces between the lines correspond with the interruptions in the conductivity between 27 and 28, occasioned by the commutator at 33.

In Fig. 2 the same form of interrupter as shown in Fig. 4 is used in the primary windings, and on the shaft 13 thereof I mount the additional commutator 19 as shown in Fig. 5 interposed at the central point of the transformer secondary windings 17, 18, and

which is adapted to operate in step with 11 and 12, and by its action to complete the conductivity of 17, 18, during the conductive period of one of the primary windings as 7, 8, and to interrupt said conductivity during the conductivity of 9, 10.

The derived wave from the winding 17, 18 will then be as shown in Fig. 2 at 24, whereas the impressed wave from the source 1 would be represented by a straight line 23.

The application of my interrupter in the circuit of the transformer windings and substantially at the central point thereof, is for the purpose of interrupting the current at a point of reduced voltage and therefore said interruption is retained relatively free from sparking and a transformed wave of different form in the secondary from that of the primary, or vice versa, is attained with a minimum of moving parts; and with the most economical and reliable construction.

Reference is herein made to my co-pending applications Serial Numbers 327,513, filed Sept. 30, 1919; 331,033, filed Oct. 16, 1919; 344,101, filed Dec. 11, 1919; 361,584, filed Feb. 26, 1920.

I claim:

1. In a transformation system a primary winding adapted to energization by a direct current, said winding divided at an intermediate point, and a secondary windin from which an induced current is derive in combination with a device connected to the intermediate terminals of the primary winding adapted to periodically interrupt and complete the circuit of the said primary winding.

2. In a transformation system a primary winding adapted to energization by a direct current, said winding divided at its intermediate point, and a secondary winding from which the induced current is derived, in combination with a device connected to the divided intermediate ends of the primary winding constructed and adapted to periodically interrupt and complete the circuit of the said primary winding, said interruptions timed to correspond with the period of magnetization and demagnetization of the transformer core.

3. In a transformer, a pair of oppositely wound primary windings connected in parallel and divided at intermediate points of each and having interposed at the point of division means constructed and adapted to alternately complete the circuit through one of said primary windings and interrupt the circuit of the other primary winding; and a secondary winding.

4. In a transformer, a pair of oppositely wound primary windings connected in parallel and divided at intermediate points of each and having interposed at the point of division means constructed and adapted to alternately complete the circuit through one of said primary windings and interrupt the circuit of the other primary winding, said interruptions timed to correspond with the period of magnetization and demagnetization of the transformer core.

5. In a transformer, a pair of o Wound primary windings connecte in parallel and divi ed at intermediate points of each and having interposed at the point ofdivision means constructed and adapted to alternately complete the circuit through one of said primary windings and interrupt the circuit of the other primary winding, said secondary divided at its intermediate point and provided with means constructed and adapted to make and break the circuit of said secondary at periodsjcoincident with the zero value of the induced electromotive force wave. I

6. In a transformation system a primary winding and a secondary winding and interrupting means interposed in said primary winding substantially at an intermediate point thereof, and other interrupting means interposed in said secondary Winding substantlally at an' intermediate point thereof.

7. The method of transforming a direct current impressed on the primary winding of a transformer from which a derived current is obtained, which consists of periodipositely riodically at cally interrupting said impressed current and also interrupting the derived current at the same. interrupting frequency as the impressed current interruption.

8. The method of deriving an interrupted secondary current from an impressed primary current which consists of interrupting the primary circuit and also the secondary circuit, wherein the said interruptions are of like frequency.

9. The method of transforming a direct current in a transformer having a primary and secondary winding which consists of interrupting the said primary winding pean intermediate point thereof and also interrupting the secondar winding at an intermediate point thereo 10. The method of transforming a direct current in a transformer having a primary and secondary winding which consists of interrupting the said primary winding periodically at an intermediate point thereof and also interrupting the secondary winding at an intermediate point thereof, with the same frequency as the first mentioned interruption.

In testimony whereof,I have hereunto set my1 hand at San Francisco, California, this 9t day OLOCtObGI, 1919.

GEORGE B. COLEMAN. 

